Growth hormone resistance.

Biological ineffectiveness of endogenous or exogenous growth hormone (GH) (i.e. a state or resistance) has been reported in several clinical conditions. The most typical form is Laron-type dwarfism, a hereditary disease which is clinically undistinguishable from isolated GH deficiency and which is characterized by high levels of plasma hGH but low somatomedin (SM). It is shown that the GH molecule binds normally to human liver receptors proving its normalcy. Thus the disease is due to an inability to generate active SM. States of resistance to exogenous GH by receptor occupancy exist when endogenous hormone is secreted in large amounts (newborns, acromegaly) or even normal amounts. Endorgan resistance to SM and GH such as in Pygmies represent an additional type. GH resistance is also induced by a rise in antibodies to GH by use of an impure or altered preparation or in a rare form of lack of immunotolerance to hGH, or by an enhancement of SM inhibitors as is seen in chronic renal failure or corticosteroid overdosage.